Automatic radio call apparatus



Aug. w, 1948. w. w. M GOFFIN AUTOMATIC RADIO CALL APPARATUS 2Sheets-Sheet 1 Filed Oct. 28, 1944 nukuuwu o.

ATTORNEY.

Aug. 10, 1948. w. w. M GOFFIN 2,445,943

AUTOMATIC RADIO CALL APPARATUS Filed Oct. 28, 1944 2 Sheets-Sheet 2 WuT11050 '7? Patented Aug. 10, 1948 QFFICE AUTOMATIC RADIO CALL APPARATUSWilliam Walter McGoflin, Olympia, Wash, as-

signor of one-fifth to S. S.,Baker, New York,

Application October 28, 1944, Serial No. 560,862

8 Claims. 1

This invention relates to a selector of a special type to interpret longand short pulsations, such as the dots and dashes comprising theinternational Morse code.

An object of this invention is to provide a special selector which iscomprised of standard parts embodying a stepper or steppers sointerconnected with relays of slow closing and slow opening type withspecial contact arrangement and connections to thereby form a new unitcapable of interpreting dot and dash pulsations.

Another object of this invention is to provide a device which may bepreset to any call or letter combination at the will of the operator togive an alarm or operate a local circuit only when the presetcombination of pulsations is transmitted to the selector.

A further object of this invention is to provide a selector of a specialtype that has a very wide tolerance in code speed variation, in whichthe timing of the dot and dash lengths is not accumulated when a presetarrangement is used.

A further object of this invention is to provide a selector with apreset arrangement that immediately returns to starting position uponreceipt of the first pulsation which is not in accordance with thepreset combination, and remains at the starting position until anothercharacter group of pulsations has started. When the selector has oncebeen stepped up to its final position to operate the local or alarmcircuit the selector remains in the final position until manually reset.This selector when not arranged in a preset circuit continues to advanceand differentiates in electrical pulsations on the stepper contactsdepending on whether or not the selector was pulsed by dot or dashoperating circuits to interpret the code, and automatically returning tothe starting position immediately on the space or pause which signifiesthe end of a character or letter.

To the foregoin objects, and others which may hereinafter more fullyappear, the invention consists of the novel construction, combinationand arrangement of parts, as will be more specifically referred to andillustrated in the accompanying drawings, but it is to be understoodthat changes, variations, and modifications may be resorted to whichfall within the scope of the invention as claimed.

In the drawings:

Fig. 1 is a schematic diagram of an automatic call selector constructedaccording to one embodiment of this invention.

Figure 2 is a diagrammatic view of the selector arrangement to interpretthe code.

Referring to the drawings and first to Figure 1, the numeral 50designates a conventional radio receiver which has connected to theoutput side thereof a relay RI by means of wires II and i2. The relay Rihas associated therewith a springpressed armature 13 which is normallyheld out of engagement with a pair of contacts l4 and I5. Armature I3 isconnected by means of a wire I6 to a wire ii and the latter is connectedat one end to an armature l8 associated with a signal relay R8. ArmatureI8 is spring-pressed and'normally engages a double contact l9 connectedby means of a wire 21! to wire 2!, which is connected to the negativeside of the source of electric current supply. A stepper relay R3 whichis adapted to operate a swinging contact arm is connected at one sidethereof to a wire 22, and the latter is connected to the positive sideof the electric current supply.

A slow acting dash relay R2 is connected at one side thereof to wire 22by means of a wire 23. The other sides of relays R2 and R3 are connectedtogether by means of a wire 24. Wire 24 has con nected. thereto one endof a wire 25, which at the opposite end is connected to a contact 26. Aspring-pressed armature 21 normally engages contact 2% and is associatedwith release relay RT. Armature 2'! has connected thereto a wire 28,which is connected to a wire 29. Wire 29 at one end thereof is connectedto contact i5, and at the other end thereof is electrically connectedwith a swinging contact wiping arm 35. Arm 30 is mounted on a shaft 3|and shaft 3! is normally biased to rotate in a counterclockwisedirection by means of a spring 32.

Shaft 3! has fixed thereon a ratchet 33 and a spring'pressed pawl 34,which is carried by an armature 35 adapted to be drawn towards stepperrelay R3 when the latter is energized, is adapted to rotate shaft 3! andswinging arm 30 step by step as relay R3 is energized. Ratchet 33 isheld against counterclockwise rotation under the tension of spring 32 bymeans of a springpressed rocking dog 36. Arm 30 is adapted to Wipe aplurality of contacts 31, which have conwires 39 are connected to a wire4|. Wires 38 are associated with the dot circuit, whereas wires 39 areassociated with the dash circuit. Wire 40 3 is connected to aspring-pressed armature 42 which is insulated from a second armature 43by insulation 44. The two armatures 42 and 43 are spring-pressed awayfrom relay R2 and are drawn toward relay R2 when the latter isenergized.

A contact 45 is disposed in a position for engagement with armature 42when the latter is drawn towards relay R2. Contact 45 has connectedtherewith one end of wire 45and the latter is connected to one end ofrelease relay R1. The opposite end of release relay R1 has con.- nectedtherewith one end of wire 41 and the other end of wire 41 is connectedto wire 22;

A contact 48 is disposed in a position to engage armature 43 when relayR2 is de-energized and contact 48 is connected to Wire 41'by means'of awire 49. Armature 43 is connected to one side of relay R4 which is aquick acting relay by means of a wire 50. The opposite end of relay R4is connected by means of a wire to wire 41". A resistance element 52 isinterposed in wire 45 for reducing the current voltage to relay R4. WireII- is-connected to a contact 53, which is normally disengaged from aspring-pressed armature 54.

A second armature 55 is fixed to armature 54, there being insulation 56between the two armatures 54 and 55. Armatures 54' and 55 are connectedtogether by means of a wire or electric conductor 51, and a wire 58 isconnected at one end to wire 51 and at the opposite end to contact 59.Contact 59 is normally disposed in spaced relation to an armature 60associated with relay R5 and armature 60 has connected thereto one endof a wire 6| which is connected to a wir 62. Wire 621is also connectedto wire I 1.

Relay R5 is connected by means of a wire 53 to wire 22 and the oppositeside of relay R5 is connected by means of a wire 64 to contact I4. Wire62 is connected to an armature 65, which is insulated from armature 60by insulation 66, and is normally disengaged from a contact 61 which hasconnected thereto one end of a wire 68. The other end of wire 68 isconnected to an armature 69' correlated with release relay R1 andnormally disposed out of engagement with a contact 10. Contact isconnected by means of a wire 1I to-a release circuit wire 12.

Aspring-pressed rockable switch arm 13 is connected by means of a wire14 to wire 68, and has mounted on the free end thereof a contact 11.Contact 11 is adapted to engage a stationar contact 18 when switch arm30 moves upwardly. Contact 18'has connected thereto one end of wire I1.

An insulating member I9 is carried by switch arm 13 and is disposed in aposition whereby arm 30 will engage therewith when the latter is in itsreleased or starting position, so as to thereby break the circuitbetween contacts 11 and 18,

Armature 55 is normall disposed out of engagement with a contact 80,which has one end of a wire 8| connected therewith. Wire 0| is connectedat the opposite end to a contact 82 and the latter is disposed in aposition for engagement with an armature 83 insulated by insulation 84from armature 35. Armature 83 has connected thereto one end of wire 12.

A second contact 85 is disposed in normally spaced relation to armature83 and has connected thereto one end of a wire 86. The opposite end ofwire 86 is connected to an armature 81 which is spring-pressed away fromrela R5. A contact 88 is disposed in a position to normally engagearmature 81' and contact 88has connected 4 thereto one end of a wire 89.The other end of wire 89 is connected to a wire 90. Wire 90 at one endis connected to an armature 9I associated with relay B5.

A contact 92 is disposed in a position to normally engage armature 9|and has connected thereto one end of a Wire 93, The opposite end of wire93 is connected to a second armature 94 correlated with relay R6, andinsulated from armature 81 by insulation 95. A contact 96 is disposed ina position normally disengaged from armature 94, and is connected towire 89 by means of a wire 91. Relay R6 is connected to Wire 93 by awire 98 and the opposite end of relay R6 is connected to positive wire22 by means of a wire 99.

A wire I00 is connected at one end to wire 46 and the opposite end to acontact IOI. Contact IIlI is disposed. in a. position normally engagingan armature I02, which is insulated from armatures SO'and 9! byinsulation I03 and I04, Armature E02 has connected thereto one end of awire I05, and the opposite end of wire I05 is connected to a pluralityof adjustable connectin wires- I00, which are adapted to adjustable ordetachable engagement with a plurality of spaced contacts I01.

Wire 90 is connected'at the opposite end thereto to a wire I08, whichmay be adjustably connected to a selected one of contacts I01. Wire90'is interposed in the space circuit, whereas wire I05 and wire I06 areinterposed in the no space or interval circuit. A rockable switch arm I09 is mechanically connected with and electrically insulated from shaft3|, being rockable therewith, and arm I09 has connected'thereto one endof a wire H0. Wire H0 at the opposite end thereof is connected to wire2|, which is negative side of the current source.

The last one I01 of contacts I01 has connected thereto a wire III. WireIII is also connected to a contact II2 normally engaged by an armatureII3 associated with relay R5, and insulated from armature 9! byinsulation II4. Armature I I3 has connected thereto one end of wire I I5 and the opposite end of wire H5 is connected to one side of signalrelay R8. The opposite side of signal relay R8 is connected by means ofa wire IIB to positive wire 22. An armature or switch arm H1 is moveablewith armature I 8 being insulated therefrom by insulation H8 andarmature H1 is connected by means of a wire II9 to an audible signalmember I20. The opposite side of signal I20 is connected by means of aWire I2I to positive wire 22.

In order to provide for the automatic return of switch arm 30 at the endof a letter or when an improper signal is received in receiver I0, Ihave provided a combined armature and lever I22, which is insulated byinsulation I23 from armature 39 and is disposed in confronting positionwith respect to release relay R1. Armature I22 is formed with a leverarm I24 and a pair of push rods I25 and I26 are connected to lever armE24 and engage dog 36 and pawl 34 respectively, Release relay R1 ma havethe circuit thereto manually closed by means of a manual switch I21interposed in wire 12 and normally biased to an open position.

Referring now to Figure 2, there is disclosed a modification of thisinvention wherein the signal impulses are adapted to be interpreted andimprinted by means of a teletype apparatus, or the like. The signalimpulses are transmitted over wires I28 and I29, wire I28 beingconnected to wire I30, which is connected 'between a stepper relay I3 Iand a second relay I32.

The opposite sides of relays I31 and I32 are also connected together bymeans of a wire I33. Wire I29 is connected to negative wire I34 which isconnected to a source of current supply, and wire I33 is connected bymeans of Wires I35 and I36 to a positive wire I31. Relay I32 has associated therewith an armature I38 connected by a wire I39 to wire I29,which is connected to wire I34. A contact I4! is disposed in normallyspaced relation to armature I88, the latter being springpressed tocircuit breaking position and contact I4! is connected by means of awire I42 to a swinging switch arm I43. Arm I43 is secured to a shaftI44, which has fiXBCI thereto a ratchet I45, and ratchet I45 is normallyurged to rotate in a counterclockwise direction by means of a springI48.

A dog I41, which is carried by an armature I48 associated with relayI3I, engages ratchet I45 to move switch arm I 43 step by step in aclockwise direction. A plurality of cont-acts I 49 are disposed in aposition for Wiping engagement by switch arm I43 and contacts I49 areconnected by means of wires I59 to one side of a plurality of solenoidsI5I. Solenoids I5I are provided with movable cores I52, which areextended from the solenoids and provide a locking means for a pluralityof series of type bars I53, I54, I55, I56 and I51.

The opposite sides of solenoids I52 are conneoted by means of wires I58and I59 to wire I38, which is connected to positive wire I31. The typebars I53 to I51 are actuated by means of solenoids I59, IGI, I92, I63and IE4, respectively. The solenoids I59 to I54 are connected to WireI59 by means of a wire I55. The opposite ends of solenoids I59 to I54are connected to spaced contacts I55, I51, I68, I59 and H4 by means ofwires I1I, I12, I13, I14 and I15, respectively.

A switch arm I18, which is mechanically connected to and insulated fromswitch arm I43 and shaft I44, is adapted to wipe over contacts I 55 toI18, respectively, upon rocking .or rotation of shaft I44. Switch armI15 has a wire I11 connected thereto and wire I11 is connected to acontact I18 normally engaging an armature I19 disposed in confrontingposition to a relay I80.

Armature I19, which is spring-pressed to engage contact I18 is connectedby means of a wire I'SI to negative wire I34. Relay I89 is connected bymeans of wire I49 to wire I28, and is connected by means of a wire I32to wire I35.

In order to provide for the release of switch arm I43 so that spring I48may return this arm and also arm I15 to a starting position, I haveprovided a relay I83 which is connected at one side to wire I31. Theother side of relay I83 is connected by a wire I84 to wire I11. Aspringpressed armature I85 is correlated with relay I83 and ismechanically connected by means of a flexible connector or othersuitable mean I85 to armature I48, so that when armature I85 is drawn inthe direction of relay I83 when the latter is energized, armature I48will be pulled away from relay I3I and pawl I41 will be pulled to a diengaged position with respect to ratchet I45.

In operation this device will function as follows: The impulses arereceived by receiver I and these impulses activate relay RI. On eachimpulse, that is either a dot or dash impulse, negative potential is setup through armature I3 and contact I4 to relay R5. Relay R is a quickclosing but slow releasing relay and will stay closed so long asimpulses are received in receiver III in the absence of a letter space.At the same time that relay R5 is energized, stepper relay R3 isenergized and after release thereof at the end of an impulse movesstepper swit'ch arm 39 for- Ward one step through spring action. RelayR3 receives negative potential from contact I5, wire 29, wire 28,armature 21, wire 25 and wire 24.

When relay R3 is energized, relay R2, which is a slow closing relay, isalso energized, and if the impulse is a dot impulse, the duration of theimpulse is not sufficient to activate relay R2 so that negativepotential from wire 49 remains broken at contact 45.

Dot operation Dash operation After stepper switch arm '39 moves forwardthree steps, it will engage the fourth contact 31 with which the firstdash. wire 39 is connected. Assuming that, as shown, the next threeimpulses are dash impulses, relays RI, R5, R4, R2, and R3 will beenergized and will operate. Stepper relay R3 will move stepper arm 3%forward three steps in sequence at the termination of each clashimpulse.

At the beginning of each impulse on a dash connection, negativepotential is continued from stopper arm 50, through wire 39, wire II,resistor 52, relay R4, armature 43 and contact 48 to positive wire 22.Armature 43 and contact 48 are engaged at this time because the timingrelay R2 has not yet closed. Relay R4 closes at the beginning of thedash impulse and continues the negative potential from armature 55 tocontact 88, through wire 8I to contact 82 of relay R3. R3 being closedwith the impulse, armature 83 is disengaged from contact 82, thuwithholding the negative potential from the release relay R1. If theimpulse were to be of short duration so that armature 83 engages contact82 while 55 and 89 are engaged, the release relay R1 is opera'ted.

When relay R2 .is operated by a dash impulse, the circuit to releaserelay R1 is opened by the de-energization of relay R4 which thereupondisengages armature 55 and con-tact 80. Such deenergization of relay R4is effected by the disengagement of armature 43 and contact 48 when adash impulse operates relay R2.

Rejection-Dash impulses Assume that, as shown, the device is set toinitially receive three dot impulses, but actually one of these impulsesis a dash impulse. When the improper dash impulse is thus received,release relay R1 is energized as follows: Relay R2 will be permitted toclose and armature 42 will engage contact 45 so that negative potentialto release relay R1 will flow from arm 30, wire 38, wire 45, armature42, Contact 45 and wire 46.

When release relay R1 is energized, stepper dog 34 and holding dog 36are disengaged from ratchet 33 so that spring 32 will return arm 38 tostarting position. At the same time, negative en a es:

potential to relays R3: and R! will be broken bysmovement of armature2-1 away from contact 28. The operation of relay R'I closes armature 69with contact II! which electrically locks relay R1 providing a negativereturn through armature 6'9, wire'88, armature I3, contacts 11, I8, wireII. This lock is retained until stepper arm 30 is returned by spring 32to starting position. In the event the pulsations are still coming inand relay R5'is closed, the electrical lock is still maintained afterstepper arm 30'moves armature 13 to circuit breaking position inasmuchas relay R5 will hold armature 65 against contact 61, and negativepotential is maintained through wire 68. to wire 62. When the impulsescease',"reiay-' R5 will open when a letter space occurs and negativepotential to release relay R! will be broken so that relays R2, R3, R4will again be set up for operation. This assures that after a reset ofthe stepper arm, the device will not recommence operation on part ofaletter.

Rejection-dot impulse Assuming that, as shown in Fig. 1, the device isset to receive three dots followed by three dashes, and the first threeimpulses are dots so that stepper arm 30 will have moved up three stepsas previously described, the next impulses must be dash impulses. If oneof the impulses is a dot and arm 30 is in circuit with a dash wire 39,relay R2 will not close, but relay R4 will close and negative potentialat the end of such dot will be supplied release relay R'I from wire 62,wire BI, armature 80, contact 58, wire 58, armature 55', contact 80,wire 8I, contact 82, armature 03, wire I2 and wire 48, the latter beingconnected to wire 12. It should be noted that at the end of the dot,relay R3 is released so as to engage contact 82 and armature 83. RelayR! will then operate as hereinafter described to release arm 30 foroperation by spring 3| to starting position.

Space check (relay R6) The function of relay R6 is to check the spacesor lack of spaces between characters or combinations of characters andimpulses in cooperation with relay R5. Arm I09 is mechanically connectedwith arm 30, but is insulated therefrom and moves step by step with arm30. Wires I06, which are in the no space circuit are connected toselected contacts I01, and at least one wire 838 is connected to aselected contact I01, as shown in Fig. 1.

Negative potential to release relay R1 is supplied from wire 2I, wireIIO, arm I09, contact I01, wire I08, wire I05, armature I02, contactIOI, wire I00, and wire 46. With no space between the impulses, relay R5will remain closed so that negative potential is broken between armatureI02 and contact IOI, and relay RI does not close.

If a space is made while arm I09 is on no space contact I'I, negativepotential is supplied release relay R! as follows: Relay R will openand'a-rmature I02 will engage contact IOI.

Space acceptance Wire I08 is in the space acceptance circuit and. whenarm I09 engagescontact I 01 with which wire I08 is connected, if a spaceis made between impulses relay R5 opens and armature 8I engages contact92. Negative potential is supplied to relay R6 as follows: Wire IIEI;arm I09, wire I08, wire 90, armature 9|, contact 92, wire 93, wire 98.Relay R6 will close and armature 84 will engage contact 88'. Negativecircuitwillbe broken at 81, 88, and as relay R3 is open, armature 83will be disengaged from contact 85 so that negative potential to releaserelay RI will be broken. Thus, at the beginning of the next pulsation,when R3 closes, armature 83 engages contact 85 but relay R1 is notoperated because R6 is still closed and the negative circuit is brokenbetween armature 81 and contact 88;

Assuming, however, that there is no space between the impulses when armI09 is associated with wire I08, the release relay R1 is closed asfollows: Negative potential passes from arm I08, wire I08, wire 90, wire89, contact 88, armature 8?, wire 88, contact 85, armature 83, wire "I2and wire 46. This occurs at the beginning of the next impulse whichcomes in without a sufficient space to allow R5 to release.

What is claimed is:

1. In a signalling system for identifying a transmission of Morse codeletters constituting a desired call, the combination of an alarm,electrical circuit means to operate said alarm, a dual selector deviceconnected on the one hand to dot or dash, and on the other hand tointerval or space circuits, and operating to effectively advance from astarting position to a position where it closes said electrical circuitmeans when a complete desired transmission has been received first relaymeans for actuating said selector device in the desired advance, se-condrelay means for returning the device to said starting position when animproper signal is received during said transmission, a first time delayrelay closing onincoming signals of dash length whereby the operation ofsaid first time delay relay characterizes the reception of a dash asdistinguished from a dot, non-operation thereof determining the dotcharacter of the pulsation and being operative to withhold operatingpower from said second relay means so as to permit the advance of saidselector device when said selector device has been set to a dotposition, and operation thereof permitting the advance of the selectordevice when it has been set to a dash position by similarly withholdingoperating power to said second relay means, a second time delay relayoperated by incoming signals and releasing at signal interruptions ofspace length whereby the release of said second time delay relaycharacterizes the reception of a space as distinguished from aninterval, non-release thereof determining the interval character of theinterruption so as to permit the advance of said selector device when itis set to interval position by withholding operating power from saidsecond relay means and operation thereof permitting the selector deviceto advance when set to space position by similarly withholding operatingpower from said second relay means whereby both of said time delayrelays are operable on said second relay means so as to cause saidselector device to be returned to starting position when an impropercharacter or interruption is received.

2. In a signalling system for identifying a transmission of Morse codeletters constituting a desired call, the combination of an alarm,electrical circuit means to operate said alarm, a selector deviceoperating to'progress in steps from a starting position to a positionwhere it closes said electrical circuit means when a completepredetermined transmission has been received, a release relay'forreturning said selector device to said starting position when anundesired call is received, said selector device comprising a firstseries of switch elements for pre-selecting the desired dot and dashcharacters, a second series of switch elements for pre-selecting thespace and interval interruptions and a pair of mechanically gangedswitch arms for progressing along the respective series of switchelements as the proper pulsations from said transmission are applied tosaid system, a slow closing relay energized by said pulsations andoperative to close when a pulsation of dash length is received, saidrelease relay being operated by said slow closing relay through said.first series of switch elements according to the pre-se1ection of saiddot and dash characters thereon, a slow releasing relay energized ateach received pulsation and operative to open at a signal interruptionof space length, said release relay being operated by said slowreleasing relay through said second series of switch elements accordingto the pre-selection of said space and interval interruptions thereon, aspring normally urging said selector device to its starting positionwhen an improper signal component is received during said, transmission,a pawl for maintaining sai-d selector device in a progressed positionagainst the action of said spring, said release relay when operated byeither said slow closing or slow releasing relay being operable uponsaid pawl so as to permit the return to starting position of saidselector device.

3, In a signalling system for identifying a transmission of Morse codeletter pulsations constituting a desired call, the combination of analarm, electrical circuit means to operate said alarm, a selector deviceoperating to progress in steps from a starting position to a positionwhere it closes said electrical circuit means when a completepredetermined transmission has been received, release relay means forreturning said selector device to said starting position when an Iundesired call is received, said selector device comprising a firstseries of switch elements for pre-selecting the desired dot and dashcharacters, a second series of switch elements for pre-selecting thepace and interval interruptions and switch arm means for progressingalong the respective series of switch elements as the proper pulsationsfrom said transmission are applied to said system, a slow closing relayenergized by said pulsations and operative to close when a pulsation ofdash length is received, said release relay means being operated by saidslow closing relay through said first series of switch elementsaccording to the pre-selection of said dot and dash characters thereon,a slow releasing relay energized at each a received pulsation andoperative to open a signal interruption of space length, said releaserelay means being operated by said slow releasing relay through saidsecond series of switch elements according to the preselection of saidspace and interval interruptions thereon, non-operation of said slowclosing and slow releasing relays respectively determining the dot andinterval natures of a received pulsation.

4. In a signalling system for identifying Morse code signaltransmissions, the combination of an alarm, electrical circuit means tooperate said alarm, a selector device including a spaced series ofcontacts and operating to effectively progress along said contacts froma starting position to a position where it closes said electricalcircuit means when a complete desired transmission has been received, aninput circuit for feeding said transmission in the form of impulses tothe apparatus, a slow closing timing relay connected to said inputcircuit so as to commence operation thereof each time an impulse is fedby said input circuit and whereby closing of said relay characterizesthe reception of a dash as distinguished from a dot, a slow releasingtiming relay operated by and closing with each said impulse, and openingat signal interruptions of space length whereby the opening of said slowreleasing timing relay characterizes the reception of a space asdistinguished from an interval, said spaced series of contacts servingas dot, dash, interval and space pre-connection means whereby saidselector device may be electrically pre-connected according to thedesired progression of signal components, each of said timing relaysincluding electrical contacts for establishing predetermined electrica1circuits according to the respectiv operation or non-operation of eachof said timing relays as determined by said fed impulses, saidpredetermined electrical circuits being formed between said timingrelays and said pre-connection means of said selector device during itsprogressive action, selector device actuating means for driving saidselector device in the desired progression until said alarm is operated,release relay means operative on said selector device for returning itto said starting position when an incoming signal component does notcorrespond to the pre-connection of said selector device, sai-d releaserelay means having an operating winding included in, so as to beoperated by, one of said predetermined electrica1 circuits according tothe pre-connections of said selector device and the respective operationof said timing relays, said one predetermined electrical circuit beingformed by said pre-connection means and the electrical contacts of saidtiming relays when the action of said timing relays as determined bysaid fed impulses does not correspond to the pre-connections of saidselector device, non-operation of said release relay means permittingsaid desired progression.

5. A signalling system according to claim 4 and including a third relaycontrolled by said slow closing relay, said third relay having a Windingconnected through said input circuit and said preconnection means so asto be energized at each incoming impulse when a dash character ispreselected and being controlled by said slow closing relay so as to bede-energized when a dash is received, said de-energization thereofwithholding operating power from said release means, and a fourth relaycontrolled by said slow releasing relay, said fourth relay having awinding connected through contacts of said slow releasing relay so as tobe energized when a space is preselected and occurs in the transmission,the energization of said fourth relay similarly withholding operatingpower from said release means when said selector device is pre-connectedto select spaces.

6. A signalling system according to claim 5 and wherein said selectordevice comprises two series of switch contacts, one of said series ofswitch contacts representing the dot and dash circuits of the systemwhereby the selector device may be pre-connected to select both the dotsand dashes in a desired transmission, and the other of said series ofswitch contacts representing the interval and space circuits of thesystem whereby the selector device may be pre-connected to select boththe intervals and spaces of the desired transmission, and a pair ofmechanically linked switch arms for respectively progressing over bothseries of switch contacts.

7. Asignalling-system according .to claim6 and wherein said selectordevice actuating means comprises another relay, both of said timingrelays, and said selector device actuating relay .being simultaneouslyfed bylincoming impulses from said input circuit.

8. 1m a signalling system for identifying a transmission of Morsecodeletter pulsations constituting a desired call, the combination of 'analarm, electrical circuit means to operate said alarm, aselector deviceoperating to progress in stepsfrom astarting position to a positionwhere it closes said electrical circuit means when a .completepredetermined transmission has been received, release relay means forreturning said :selector device to said starting position whenanundesired call is -received,,said selector device comprising a firstseriesof switch elements preconnected was to pre-selectthe desired dotand "dash characters, 'a'rsecond series of switch elemnentspreconnect-ed so as to pre-select the space "and interval interruptionsand switch arm means for progressing along the respective series ofswitch-elements as the proper pulsations from ---said transmission areapplied to said system, a first ,timing relay op erating to :distinguishbetween received-:dot and :dash impulsespand beingopercatively'connected to said "release relay meansiaccordingivtoathe"preaselectionlof said dot and dash 'chara'cters,andrasecondtiming relay operating: to adistinguishbetween received spaceand interval interruptions, and .being operatively connected-tosaidrelease relay-means according to the preesel'ection of said spaceand interval interruptions, said first timing relay being a slow closingrelay which is energized by received pulsations and -has' adelay-time-so that operation or ions-operation of said slowclosing relayrespectively determines ,thcdotor dash nature of a receivedpulsation,said ,second timing relay being a slowreleasingrelay energized at eachreceived pulsation and having-a delay time so that-operation ornon-operation of said slow releasing relay respectively determines thespace or interval na- .ture of an interruption in the signaltransmission, afirst associated relay cooperating-with said first timingrelayand operative to withhold operating power to said release relaymeans when an incoming dot or-dash pulsation corresponds to thepro-connections of said first series of switch elements, and a secondassociated relay cooperating with said second timing relay so as tosimilarly withhold operating power to said release relay means when anincoming space or interval interruption corresponds to the,pre-connections of said second series of switch elements.

WILLIAM WALTER MoGOFFIN.

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